Diagnostic and therapeutic lenses are commonly used in ophthalmology for evaluation and treatment of the internal portions of the eye. In order to effect treatment for a variety of ocular disorders, an ophthalmologist must first see the inner structure of the eye. After an appropriate examination is completed, a laser delivery system may be used, e.g., to thermally heat the appropriate anatomical structures within the eye with laser light. Prior technology often includes a slit lamp biomicroscope used in conjunction with specialized ophthalmic instruments (devices) and special eye-contacting lenses. These lenses are designed to view different anatomical areas within the eye. The patient's pupil is usually pharmacologically dilated, topical anesthesia is placed on the eye, a coupling agent is placed on the posterior surface of the lens, and the examiner holds the lens over the surface of the eye.
During use, the instruments of the aforementioned type are brought in direct contact with the cornea of the patient's eye. In order to prevent transfer of infections from patient to patient, such optical instruments, especially the eye-contacting portions thereof, must be properly sterilized before use. The sterilization procedure most widely used in practice is treatment in an autoclave. However, since sterilization in an autoclave is a high-temperature procedure, such treatment may be undesirable for optical instruments that have optical materials, bondings, and coatings degradable under the effect of high temperatures.
Devices used in ophthalmology for intraocular observations include a line of wide-angle lenses, gonio lenses, capsulatomy and iridectomy lenses, laser photocoagulation lenses, etc.
Observation of the anterior chamber and especially its angled areas, which are difficult or impossible to see with the use of some conventional optical means, is very important for diagnosis of eye diseases. For example, the classification of glaucoma relies heavily on knowledge of anterior segment anatomy, particularly that of the anterior chamber angle.
The anterior chamber of a human eye is commonly evaluated during slit lamp biomicroscopy, but the chamber angle is hidden from ordinary view because of total internal reflection of light rays emanating from the angled structures. In other words, without gonioscopy, additional diagnostic clues of disease are forever hidden from ordinary view. Additional effort, skill, and patient cooperation are required to view the normally concealed chamber angle by either indirect (angled structures viewed through a mirror) or direct (angled structures viewed directly) gonioscopic techniques. In other words, without gonioscopy, it is impossible to classify glaucoma properly.
An example of a typical, solid, i.e., monolithic, gonioscope is shown in U.S. Pat. No. 6,767,098 issued in 2004 to Ph. Erickson, et al. The gonioscope has an optically transparent body, the distal end has a viewing surface preferably oriented perpendicularly to the optical axis of the body, the proximal end of the prism has a concave surface with a curvature similar to the curvature of a patient's cornea. The proximal end has at least one planar surface extending outwardly and distally from a location adjacent to the periphery of the concave surface. The body has an index of refraction that provides total internal reflection to a viewer looking through the viewing surface even when the planar surface is at least partially moistened with a fluid.
Common to wide-angle lenses, gonio lenses, capsulatomy and iridectomy lenses, and laser photocoagulation lenses is the provision of an eye-contacting lens that during observation or surgical treatment is maintained in physical contact with the eye cornea. Such optical devices require sterilization after use, especially with regard to the eye-contacting surfaces and especially when the optical device is intended for surgical use.